1. Field of the Invention
The invention relates to a system for mixing a first fluid with one or more additional fluids and for dispensing the mixed fluids.
2. Description of the Related Art
Chemical dispensing systems are known in which the chemicals are supplied in concentrated form, such as solid, liquid, granulated, or powdered, and the chemical concentrate is mixed with a diluent such as water to form ready to use formulations that are thereafter distributed to a site. Preferably, the dilution ratio of chemical concentrate and diluent is carefully controlled to ensure optimum performance of the formulation at the site where the formulation is applied.
The dilution ratio of chemical concentrate and diluent can be controlled using a time-based approach. For example, a diluent pump may be run for a certain period of time to provide diluent to a mixing chamber, and a concentrate pump may be run for a certain period of time to provide concentrate to the mixing chamber. The time for operation for the diluent pump and the concentrate pump can be programmed into a control unit of the chemical dispensing system, under the assumption that the dispensed volume of diluent and concentrate over time will be consistent through repeated dispensing cycles. This type of fluid dispensing is common in the food and beverage industry. However, there are a number of problems with a time-based approach to volumetric control. Often, the volumetric flow generated by pumps is not precise, which can lead to inconsistent dispensed volume of diluent and concentrate over different dispensing cycles.
It has been proposed to use flow meters downstream of the diluent pump and the concentrate pump in a chemical dispensing system to more precisely control the dispensed volume of diluent and concentrate into a mixing chamber. However, the use of flow meters may not provide enough precision to eliminate inconsistent dispensing of diluent and concentrate over different dispensing cycles.
Certain sterilizing formulations used in the medical, veterinary and dairy fields must have a very consistent ratio of active sterilizing agent to diluent (e.g. water) in order to avoid irritating a body part being sterilized. For example, higher levels of sterilizing agent relative to diluent may lead to such irritation. In addition, poor mixing of the diluent and the concentrate in a chemical dispensing system may lead to an inconsistent ratio of diluent and concentrate throughout the volume of fluid in the mixing chamber. As a result, the ratio of diluent and concentrate will vary as the fluid in the mixing chamber is dispensed.
Therefore, there exists a need for a system for dispensing a mixture of a concentrate and a diluent in which the system provides more precise control of the ratio of diluent and concentrate in the mixed fluid.